Various designs and techniques have been developed in the past for accelerating and launching a projectile. For example, U.S. Pat. No. 3,431,816 to Dale concerns an electric augmented gun-firing system. The system is generally made up of a barrel and a breech block. A power supply is generally made up of a first pair of arc-discharge electrodes and a second pair of inductor-operated arc-discharge electrodes. The electrodes are operatively associated with the breech and barrel of the system such that upon filling the firing chamber with a pressurized and ignitable gaseous medium and then operating the power supply, a portion of the gas is ionized and continuously sustained so as to form a longitudinally advancing and pressurized wave front that causes acceleration and launching of a projectile from the barrel. U.S. Pat. No. 3,613,499 to Hubbard et al. concerns a projectile acceleration system. The system is generally comprised of a barrel. The barrel at least at one preselected point includes a capacitance augmenting station. The station is generally made up of a pair of diametrically opposed electrodes and a gas-rupturable diaphragm seal associated with each electrode. A projectile is initially accelerated in some fashion by a pressurized and ionized gas. As the projectile advances past a station in the barrel bore, the pressurized gas ruptures the diaphragms thereby enabling an arc to be discharged between the electrodes for further energizing the gas and thus cause continued and increased acceleration of the projectile. U.S. Pat. No. 3,916,761 to Fletcher discloses a meteroid simulation apparatus. The apparatus generally comprises a combined initial projectile-acceleration barrel arrangement and a subsequent plasma-generator, projectile-acceleration device. The barrel arrangement includes a powder cartridge for compressing inert gas to initially accelerate a projectile. The plasma device is provided with a pair of electrodes for timely transforming a metal foil into a plasma and then further energizing and densifying the plasma by an electromagnetic coil so as to finally accelerate the gas-fired projectile to a hypervelocity for simulating a meteroid. U.S. Pat. No. 4,429,612 to Tidman et al. concerns a multistation electrode apparatus within a controlled and ionizable gaseous medium for accelerating a projectile of special-shaped, conical-like configuration. However, none of the aforediscussed references, whether taken alone or in any combination, remotely suggest an improved gun-firing system which is provided with a chamber for receiving propellant and a projectile, and which is also provided with helically wound electromagnetic coil about and along the chamber for inducing heating of the plasma of the ignited propellant in the chamber so as to further pressurize same for causing launching of the projectile at a higher velocity from the gun. In another embodiment, the breech of the system is provided with a pair of electrodes of special and different construction for generating a sustained and expanding arc across the chamber between its ends so as to further heat and pressurize the plasma in order to increase the velocity of the projectile as it exits from the gun.